2, 3-alkylenedioxy-6-nitro-9-aminoacridines and their synthesis



United States PatentfO 2,3-ALKYLENEDIOXY-6-NITRO-9-A1VHNOACRI- DTNES AND THEIR SYNTHESIS Edgar Alfred Steck, Guilder-land, N. Y., assignor to Sterling Drug: Inc., New York, N. Y., a corporation of Delta ware No Drawing. Application October 27, 1953, Serial No. 388,700

11 Claims. (Cl. 260-279) This invention relates to 2,3-alkylenedioxy-6-nitro-9- aminoacridines and to their synthesis.

These compounds of my invention have in free base form the structure where n is an integer from one to two. These compounds have been found to possess valuable chemotherapeutic properties, for instance, antirickettsial activity.

My 2,3-alkylenedioxy-6-nitro-9-aminoacridines were prepared preferably by heating a mixture of phenol and the appropriate 2,3-alkylene-dioxy-6-nitro-9-haloacridine to form the corresponding 2,3-alkylenedioxy-6-nitro 9 phenoxyacridine as the hydrohalide, which did not need to be isolated, and then heating the 2,3-alkylenedioxy-6- nitro-9-phenoxyacridine hydrohalide with an aminating agent, i. e., a compound which on heating produces available ammonia, such as ammonium carbonate, ammonium bicarbonate, ammonium carbamate, ammonium acetate, and the like. In carrying out my invention, I preferred to use commercial ammonium carbonate which actually is a mixture of ammonium bicarbonate and ammonium carbamate (see page 62 of the Sixth Edition of The Merck Index, Merck & Co., Inc., Rahway, N. J., 1952 or page 810 of the Fourth Edition of Ephraims Inorganic Chemistry, Nordeman Publishing Co., Inc., New York, N. Y., 1943). Illustrative of this preparation is the reaction of 2,3-methylenedioxy-6-nitro-9-chloroacridine with phenol to form 2,3anethylenedioxy-6-siitro-9-phenoxyacridine mono hydrochloride which on treatment, in either pure form or crude form (as directly obtained from the reaction mixture of the first step), with commercial ammonium carbonate yields 2,3-methylenedioxy-6-nitro-9- aminoacridine.

Alternatively, but not as satisfactorily, the 2,3-alkylenedioxy-6-nitro-9-aminoacridines of my invention can be prepared by directly heating the appropriate 9-haloacri'dine with an aminating agent such as commercial ammonium carbonate, without first reacting the former compound with phenol.

The preparation ofmy 2,3-alkylenedioxy-6-nitro-9- aminoacridines was carried out under acidic conditions. When the reactant was a 2,3-alkylenedioxy-6-nitro-9-haloacridine, an acidic medium was afforded by the presence of the hydrohalic acid formed in the reaction. When the reactant was a 2,3-alkylenedioxy-6-nitro-9-phenoxyacridine, acidic conditions were produced either by using the 9-phenoxy compound in the form of its hydrohalic acid addition salt or by adding a small amount of a mineral acid.

The 2,3-alkylenedioxy-6-nitro-9-aminoacridines of my invention are therapeutically active whether employed in the form of their free bases or in the form of their salts ice Example 1 (a) 2,3-methylenedi0xy-6-nitr0-9-chl0r0acridine.-This compound was prepared by first heating 2-chloro-4-nitrobenzoic acid with 3,4-methylenedioxyaniline in the presence of copper powder to produce 2-(3,4-methylenedioxyphenylamino)-4-nitrobenzoic acid, which was then heated in toluene solution with phosphorus oxychloride to efiect ring closure. These procedures are given in the following paragraphs:

A solution of 98.5 g. of anyhdrous potassium carbonate in m1. of water was heated to 60 C. with stirring. To this solution was added 144 g. of 2-chloro-4-nitrobenzoic acid, followed by 8 g. of copper powder, 8 g. of a filter aid such as Filtercel (an infusorial earth), and 98.5 g. of 3,4-methylenedioxyaniline dissolved in 500 ml. of ethanol. Ethanol was then removed by distillation until an internal temperature of 95 C. was reached, and the resulting solution was refluxed for five hours. The reaction mixture was steam distilled to remove any unreacted aniline derivative. The aqueous residue was filtered while hot and the collected solid was extracted three times with boiling water. The combined filtrate and extracts were chilled in an ice bath and acidified with an excess of concentrated hydrochloric acid. The red solid that separated was collected and purified by recrystallization from acetone-water. There was thus obtained 106.3 g. of 2-(3,4-methylenedioxyphenylamino) 4 nitrobenzoic acid, M. P. 240-241 C.

AnaZysis.-Calcd. for C14H10N2Os: C, 55.63; H, 3.34; N, 9.27. Found: C, 55.52; H, 3.36; N, 9.40.

Ring closure was eeffected as follows: 106.3 g. of 2- (3,4 methylenedioxyphenylamino)-4-nitrobenzoic acid was dissolved in 1064 ml. of toluene. The solution was heated to reflux, heating stopped, and g. of phosphorus oxychloride was added over a fifteen minute period. Heating was resumed at gentle reflux with stirring for three and one-half hours. The reaction mixture was cooled and the precipitate that separated was collected. The precipitate was added over a thirty minute period to a chilled (0 C.) solution containing 310 ml. of 10% aqueous sodium hydroxide solution and 410 mlof water. The mixture was stirred for an additional two hours at 0 C. The solid was collected, triturated with ammonium hydroxide solution, washed with cold water and recrystallized from chlorobenzene. There was thus obtained 6 7.5 g. of 2,3-methylenedioxy-6-nitro-9-chloroacridine, M. P. 300301 C.

Analysis.Calcd. for C14H7N2C1O4: C, 55.55; H, 2.33; Nno 4.63; Cl. 4.71. Found: C, 55.51; H, 2.33; NNO2' 4.57; CI. 11.82.

The above 2,3-methylenedioxy-6-nitro-9-chl0roacridine and the corresponding 2,3-ethylenedioxy-6-nitro-9-chloroacridine of Example 2 (a) are disclosed and claimed in my copending U. S. application, Serial Number 388,698, filed October 27, 3.

(b) 2,3-mezhylenedi0xy-6-nitr0-9-aminoacridine.--To a stirred solution of 12.1 g. of 2,3-methylenedioxy-6-nitro- 9-chloroacridine dissolved in 43 g. of phenol kept at a temperature of about 75 C. was added 5.2 g. of powdered ammonium carbonate, whereupon the temperature raised rapidly to about 120 C. The reaction mixture was kept at this temperature for about forty-five minutes, chilled to 30 C., and then poured into a solution containing a mixture of 120 ml. of acetone and 30 ml. of concentrated hydrochloric acid. The orange solid that separated was washed respectively with acetone and an ether solution of hydrogen chloride, and was recrystallized from Water to which was added a solution of hydrogen chloridee in acetone. The resulting golden-colored product, 2,3-methy1- enedioxy-6-nitro-9-aminoacridine as its hydrochloride, melted at 250-251 C. with decomposition.

Analysis.-Calcd. for C14H9N3O4.HC1: Nno 4.36; CI, 11.09. Found; NNOZ, 3.54 and 3.58; Cl, 9.42.

Following the above procedure in the absence of phenol, i. e., heating 2,3-methylenedioXy-6-nitro-9-ch1oroacridine directly with powdered ammonium carbonate, the same product, 2,3 methylenedioxy-6-nitro-9-aminoacridine in the form of its monohydrochloride, can be obtained.

Example 2 (a) 2,3-ethylenedioxy-6-nitr0-9-chloroacridine.--This compound was prepared following the procedure described under Example 1 (a), as follows:

2(3,4-ethy1enedioxyphenylamino)-4-nitrobenzoic acid was prepared using 124 g. of anhydrous potassium carbonate in 182 ml. of water, 180 g. of 2-chloro-4-nitrobenzoic acid, 6 g. of copper powder, and 136 g. of 3,4- ethylenedioxyaniline in 1300 ml. of methanol. The product was obtained as golden-brown needles, M. P. 249- 250.5 C. (cor.) when recrystallized from ethanol-water.

Analysis.Ca1cd. for C15H12N2062 C, 56.96; H, 3.38; Nuo 4.43. Found: C, 57.23; H, 3.53; Nno 4.32.

Ring closure was eflected as in Example 1 (a) using 86 g. of 2-(3,4-ethylenedioxyphenylamino)-4-nitrobenzoic acid, 945 ml. of toluene and 113 g. of phosphorus oxychloride. The product, 2,3-ethylenedioxy-6-nitro-9- chloroacridine, melted at 282284 C. with decomposition when recrystallized from chlorobenzene.

Analysis.-Calcd. for C15H9N2O4Cl: C, 56.88; H, 2.87; Cl, 11.19. Found: C, 57.42; H, 2.87; CI. 11.50.

(b) 2,3-ethylenedioxy-o-nitr-9-amin0acridine.-Tl1is preparation was carried out following the procedure described above for Example 1 (b) using 12.7 g. of 2,3- ethylenedioxy-6-nitro-9-chloroacridine, 43 g. of phenol and 5.2 g. of powdered ammonium carbonate. The crude product thus obtained (16.0 g.) was crystallized by dissolving it in 800 ml. of water at 80 C. and adding 20 ml. of concentrated hydrochloric acid to the filtered solution. A second recrystallization in the same manner yielded, as brick red microcrystals, 2,3-ethylenedioxy-6-nitro-9- aminoacridine in the form of its monohydrochloride, M. P. above 300' C.

Analysis.-Ca1cd. for C15H11N3O4.HC1: N, 12.59; Cl, 10.62. Found: N, 12.60; Cl, 10.68.

The above 2,3-alkylenedioxy-6-nitro-9-aminoacridines of my invention have antirickettsial activity, e. g., against epidemic typhus, as determined by the chick embryo technique.

I claim:

1. A compound selected from the group consisting of a 4 2,3-alkylenedioxy-6-nitro-9-aminoacridine having the structure I NH:

where n is an integer from one to two, which comprises heating a member of the group consisting of the corresponding 2,3-alkylenedioxy-6-nitro-9-haloacridine and 2,3 alkylenedioxy-6-nitro-9-phenoxyacridine with aminating agent under acidic condition.

5. The process of preparing a 2,3-alkylenedioxy-6- nitro-9-arninoacridine having the formula where n is an integer from one to two, which comprises heating the corresponding 2,3-alkylenedioxy-6-nitro-9- phenoxyacridine with an aminating agent under acidic conditions.

6. The process of preparing 2,3-methylenedioxy-6-nitro- 9-aminoacridine which comprises heating 2,3-methylenedioxy-6-nitro-9-phenoxyacridine hydrochloride with an aminating agent.

7. The process of preparing 2,3-ethylenedioxy-6-nitro- 9-aminoacridine which comprises heating 2,3-ethylenedioxy-6-nitro-9-phenoxyacridine hydrochloride with an aminating agent.

8. An acid addition salt of 2,3-methylenedioxy-6-nitro- 9-aminoacridine.

9. An acid addition salt of 2,3-ethylenedioxy-6-nitro-9- aminoacridine.

10. 2,3-methylenedioxy-6-nitro-9-aminoacridine monohydrochloride.

11. 2,3-ethylenedioxy6-nitro-9-aminoac1'idine monohydrochloride.

References Cited in the file of this patent UNITED STATES PATENTS 1,962,277 Jensch June 12, 1934 2,531,010 Surrey 2. Nov. 21, 1950 2,531,012 Surrey Nov. 21, 1950 2,647,900 Surrey Aug. 4, 1953 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF A 2,3-ALKYLENEDIOXY-6-NITRO-9-AMINOACRIDINE HAVING THE STRUCTURE 